(1) Field of the Invention
The present invention relates to a novel apparatus and method for providing tensile strength to longitudinal sections of cables, including cables in which a linear energy transmission medium has a surrounding arrangement of a damage resistant outer sheath with emollient liquid between the sheath and the transmission medium. It also relates to such providing tensile strength to forms of cable section assemblies having a layer of flexible molded material between the damage resistant sheath and the central core structure containing the transmission medium. An example of the latter type of cable section assembly is disclosed in U.S. Pat. No. 6,426,464, issued 30 Jul. 2002, and especially therein in a discussion of a best mode of that invention for applications of that invention in which the cable section assemblies are used in environments in which they are extremely stressed (especially see the description therein at column 12, line 65 through column 18, line 4). This U.S. Pat. No. 6,426,464 is hereby incorporated herein in its entirety. An aspect of the invention is also of special utility in providing tensile strength to cable section assemblies for microwave coaxial lines.
(2) Description of the Prior Art
Submarines must be able to send and receive messages. Radio reception from a submerged submarine is maintained through a buoyant cable antenna (“BCA”) which comprises an antenna line train of components including at least at the trailing end thereof a detachably connected longitudinal sectional component. The BCA rises above the submarine and floats and streams at or near the ocean surface. When not in use, the BCA is coiled around a small diameter spool in the submarine, requiring considerable flexibility. When deployed from the submarine, the BCA and its components require a demanding structure due to the substantial stress placed on the BCA. For example, the BCA is subjected to severe mechanical shocks when towed in high sea conditions, e.g., the BCA must rise from various depths and may be subjected to waves of up to 35 feet at the ocean surface. Thus, tensile strength is critical to the BCA structure.
Prior art BCA cable section assemblies elements are known wherein the tensile strength was augmented by the provision at their respective ends of cable-end grips of the type affixing to core structures of the assembly by open-mesh-sleeves which tightened their constriction on the core structure by Chinese-finger-toy like tightening of the mesh sleeve around a grip foundation sleeve molded on the core structure. Also a prior attempt was made to increase the tensile strength and flexing damage resistance characteristics of BCA cable section assemblies was by potting the length of core structure in cured flexible polyurethane, which is moldingly bonded to the grip foundation gripped by the open-mesh-sleeves of the cable-end gripping device. However, the prior attempt using this approach did not provide a significantly improvement over the tensile strength and flexing damage avoidance capabilities provided by the grip sleeves and grip foundation alone.
Accordingly, there is an unsatisfied need for a cable section assembly of a BCA having an imbedded coaxial cable which has higher tensile strength and flexing damage resistance characteristics than heretofore available by application of the foregoing known prior art, and attempted approach of of improvement, of insertion of a moldingly bonded grip foundation into an open-mesh-sleeve type cable end grip.
There are additional prior art devices relating to various types of cable assemblies or reinforcing members which do not involve gripping by open-mesh-sleeves such as disclosed in U.S. Pat. Nos. 2,352,391; 4,463,358; 4,491,939; 4,749,420 and 5,057,092. Thus, for example, U.S. Pat. Nos. 4,463,358 and 4,749,420 generally disclose basic buoyant cable antennas. Additionally, U.S. Pat. Nos. 2,352,391, 5,057,093 and 4,634,804 generally disclose the use of spaced elongated strengthening members. U.S. Pat. No. 4,491,939 generally discloses a cable using a Kevlar® member.